[deliverable/linux.git] / arch / x86 / realmode / rm / trampoline_32.S

/*
 *
 *	Trampoline.S	Derived from Setup.S by Linus Torvalds
 *
 *	4 Jan 1997 Michael Chastain: changed to gnu as.
 *
 *	This is only used for booting secondary CPUs in SMP machine
 *
 *	Entry: CS:IP point to the start of our code, we are
 *	in real mode with no stack, but the rest of the
 *	trampoline page to make our stack and everything else
 *	is a mystery.
 *
 *	We jump into arch/x86/kernel/head_32.S.
 *
 *	On entry to trampoline_start, the processor is in real mode
 *	with 16-bit addressing and 16-bit data.  CS has some value
 *	and IP is zero.  Thus, we load CS to the physical segment
 *	of the real mode code before doing anything further.
 */

#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/page_types.h>
#include "realmode.h"

	.text
	.code16

	.balign	PAGE_SIZE
ENTRY(trampoline_start)
	wbinvd			# Needed for NUMA-Q should be harmless for others

	LJMPW_RM(1f)
1:
	mov	%cs, %ax	# Code and data in the same place
	mov	%ax, %ds

	cli			# We should be safe anyway

	movl	tr_start, %eax	# where we need to go

	movl	$0xA5A5A5A5, trampoline_status
				# write marker for master knows we're running

	/*
	 * GDT tables in non default location kernel can be beyond 16MB and
	 * lgdt will not be able to load the address as in real mode default
	 * operand size is 16bit. Use lgdtl instead to force operand size
	 * to 32 bit.
	 */
	lidtl	tr_idt			# load idt with 0, 0
	lgdtl	tr_gdt			# load gdt with whatever is appropriate

	movw	$1, %dx			# protected mode (PE) bit
	lmsw	%dx			# into protected mode

	ljmpl	$__BOOT_CS, $pa_startup_32

	.section ".text32","ax"
	.code32
ENTRY(startup_32)			# note: also used from wakeup_asm.S
	jmp	*%eax

	.bss
	.balign 8
GLOBAL(trampoline_header)
	tr_start:		.space	4
	tr_gdt_pad:		.space	2
	tr_gdt:			.space	6
END(trampoline_header)
	
#include "trampoline_common.S"
Commit	Line	Data
48927bbb JS	1	/*
	2	*
	3	* Trampoline.S Derived from Setup.S by Linus Torvalds
	4	*
	5	* 4 Jan 1997 Michael Chastain: changed to gnu as.
	6	*
	7	* This is only used for booting secondary CPUs in SMP machine
	8	*
	9	* Entry: CS:IP point to the start of our code, we are
	10	* in real mode with no stack, but the rest of the
	11	* trampoline page to make our stack and everything else
	12	* is a mystery.
	13	*
	14	* We jump into arch/x86/kernel/head_32.S.
	15	*
f37240f1	16	* On entry to trampoline_start, the processor is in real mode
48927bbb JS	17	* with 16-bit addressing and 16-bit data. CS has some value
	18	* and IP is zero. Thus, we load CS to the physical segment
	19	* of the real mode code before doing anything further.
48927bbb JS	20	*/
	21
	22	#include <linux/linkage.h>
48927bbb JS	23	#include <asm/segment.h>
48927bbb JS	24	#include <asm/page_types.h>
e5684ec4	25	#include "realmode.h"
48927bbb JS	26
	27	.text
	28	.code16
48927bbb	29
8e029fcd	30	.balign PAGE_SIZE
f37240f1	31	ENTRY(trampoline_start)
48927bbb JS	32	wbinvd # Needed for NUMA-Q should be harmless for others
48927bbb JS	33
e5684ec4	34	LJMPW_RM(1f)
48927bbb JS	35	1:
	36	mov %cs, %ax # Code and data in the same place
	37	mov %ax, %ds
	38
	39	cli # We should be safe anyway
	40
f37240f1	41	movl tr_start, %eax # where we need to go
968ff9ee	42
48927bbb JS	43	movl $0xA5A5A5A5, trampoline_status
	44	# write marker for master knows we're running
	45
968ff9ee PA	46	/*
968ff9ee PA	47	* GDT tables in non default location kernel can be beyond 16MB and
48927bbb JS	48	* lgdt will not be able to load the address as in real mode default
	49	* operand size is 16bit. Use lgdtl instead to force operand size
	50	* to 32 bit.
	51	*/
f37240f1 JS	52	lidtl tr_idt # load idt with 0, 0
f37240f1 JS	53	lgdtl tr_gdt # load gdt with whatever is appropriate
48927bbb	54
968ff9ee PA	55	movw $1, %dx # protected mode (PE) bit
968ff9ee PA	56	lmsw %dx # into protected mode
48927bbb	57
968ff9ee PA	58	ljmpl $__BOOT_CS, $pa_startup_32
	59
	60	.section ".text32","ax"
	61	.code32
	62	ENTRY(startup_32) # note: also used from wakeup_asm.S
	63	jmp *%eax
48927bbb	64
51edbe6a PA	65	.bss
	66	.balign 8
	67	GLOBAL(trampoline_header)
	68	tr_start: .space 4
	69	tr_gdt_pad: .space 2
	70	tr_gdt: .space 6
	71	END(trampoline_header)
	72
f37240f1	73	#include "trampoline_common.S"